Block-signal system.



L. A. HAWKINS.

BLOCK SIGNAL SYSTEM.

APPLICATION rnnn 0012a, moo.

Patented May 21, 1912.

2 SHEETS-SHEET 1.

I H ha'anfikaf L. A. HAWKINS.

BLOCK SIGNAL SYSTEM.

APPLICATION FILED OUT-2,1009.

1,027,06. Patented May 21., 1912.

2 BHEETS SHEF-T 2.

0 Q I mTN 55275 [NS/ENTER 8M1 K 1 aw y LAUHENRE/A HAWK/N5 9' Amrcmwsy UNITED STATES PAlENT OFFICE.

LAUREIlCE A. HAWKINS, OF SCHENECTADY, NEW YORK, ASSIGNOR, BY MESNE ASSIGN.

MENTS, T0 UNION SWITCH AND SIGNAL COMPANY, A CORPORATION OF PENNSYL- VANIA.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent.

' Patented May 21, 1912.

Application filed October 2, 1909. Serial No. 520,651

.To all whom it may concern:

Be it known that I, LAURENCE A. Haw- KINS, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Block-Signal Systems, of which the following is a specification.

My invention relates to block signal systems in which the signals for the blocks are arranged to give three indications, danger, caution and clear, and are controlled wholly through the track circuits. in a prior application, Serial No. 511,663, tiled August 7 1909, I disclosed a system of this character in which currents of different phases were supplied to the track circuit of each block and a pair of track relays were provided for each block, each relay having a trackwinding and a second (:0- operating winding supplied with current independently of the track circuit, one relay being responsive to current in the track circuit from the transformer for that track circuit regardless of variations in phase in that current, and the other relay being responsive to current of one phase only. This system, as compared with prior systems for accomplishing the same results, had the advantages, first, that the relays were all of the efficient two winding type; second, that since one of the relays of each pair was not atfectedby the change in phase of the track current the changc could be made gradually so as to maintain that relay energized and hence it was unnecessary to use quick acting or snap switches for cont-rolinsulated joints between blocks, was avoidedi My present invention consists in a modification of the system of my former application. In the present ease, instead of em ploying different phases for the track currents, I employ different frequencies and so arrange the system"; that allthe advan-, tages of the system of my prior applica tion are still obtained,

My invention will best be understood by reference to the accompanying drawings, in which-- f 1 shows diagrammatically a block gt-hrough resist-inc p tween the transformers F to F and E to E signal system arranged in accordance with my invention, and Fig. 2 shows a modification of the same.

In the drawings, A, A, A and A represent the rails of four blocks. I

B, B and B represent signals at the ent -ance to blocks A, A and A, respectively. These signals are arranged to give three indications of danger,- caution or clear, either as indicated by a three-position arm or by the equivalent arrangement of two two-position arms.

C and C" represent alternating current generators of dill'crent frequencies. a, 0' and c represent transmission lines supplied with current from these generators, the conductor 0 being common to both freq uoncics.

D to l) represent track relays ,-,of which two are provided for each block. These relays are indicated diagrannnatically as of the well-known induction type each comprising a slmrt-eircuited secondary member; (Z actuating the relay contacts, a track wind ing (2 and a coiiperating winding or windings (1 supplied with current independently of the track circuits. The relays'D, D and I) are shown each with two windings (l l) to E represent transformers having their primaries connected to the transmission lines. The two\ transformers of each pair are connected to ditlerent frequencies.

F, F and F represent track transformers having their secondaries connected to, and

supplying current to, the track circuits of" ,t-he blocks ,A', A, respectively, and their {primaries adapted tobe connected-to the ling the track circuit current, and third, that by properly arranging the connections. of adjacent blocks allpossibility of a false clear signal, due to breaking down of the secondaries of the transformers E to E The connections beare controlled by contacts 7) on the signal mechanisms. The "connections between these contacts and the signals are shown diagrammatically in dotted lines.

With a train or car in hloclt' A, as indicated at H, the track; windings of relays D and D areshort-circuited, so that the relay .dntacts are open and the signal 13 stands atvdanger or stop. in this position of sig- 'nal'B its contact I) connects the primary of track transformer F to the secondary of transformer E which has the frequency of generator Cl. Relay 1) of block A has its. windings (i connected to the secondary of transformer Eiwhich has the frequency of generator C so that this relay D is not affected by the current now supplied to block A by-transformer F Relay 1) has 5 two windings 6?, one of which is connected to the secondary of transformer E which has the frequency of generator C, The current in this winding d cooperating with the current in the track winding 0? procontacts and causes signal B to move from danger to caution position. The operating mechanisms for the signals are notv shown but it will be understood that the conductor running directly from the contact of relay D 'to the upper side of thesignal blade controls the movement of the signal from step to caution, while the other conductor extending from the contacts of relay D to the upper side of; the blade controls the movement of the signal from cau- ;tion to clear, theconductor extending from the lower side of the blade being common for both circuits. With signal B in cautie? position its contact I; connects the rim 1y "of transformer F to the secon cry of transformer E, so that the current in the track circuit of block A has the frequency ,of generator C Since one of the windings d of relay D and the single winding (Z of telay D? are supplied with'current 'of this frequency both relays close. their contacts, sothat signal B stands at, clear.

'When the carnioves out of block A into the next block the condition of'relays D? and D is the same as that shown for re-' lays D and D so that signal *B will then move from sto to caution position, shifting the connecting of transformer 15 from transformer E to transformer E. The contact Z is so arranged, as indicated in the drawing, that the connection to transformenlll is made before the connection to transformer E? is broken so, that relay I) is not deenergized during this change in the connections ofthe transformer F and the switch contact t 'need not he made quick acting, ,VVhile transformer F is con-.

nccted to transformer E and E a certain amount of current flows through the secondaries of these two transformers in series, but it :flowsthrough both resistances gt and is limited in amount by these resistances. .Thcmovement of signal B from caution :to clear does not alter the connections of vtra nsformer F, so that the signal 15 is 'ficcted. In each of the. relays the portion of the current rcqfired for i'y torque may be supplied directly 'c. windings cl" so that the track cur- V .mayii' hc small. It will he noted that rack connections of each block are 1y reversed. Because of this reversal cing'v down of the insulated joints rela a b i l w en the blocks will produce a reverse duces a torque in relay 1) which closes its. nectedto the transformers ll'iq E -frequencies will be obvious to 'trackrelays per block having with .ciirre'nt independently o relays adjacent to the broken torque in the to put the signals at down joints so'as den er. I

. 2 shows amodificationof thesystcni in w ich each of the relays; has only one winding 0? in addition to the "wind ing. The windingsd of therein s of each palr are in this case supplied wit/currents of different frequencies, The track tinneformers F, F and F arepermanently eon-1 racy-E5 1 'When a signal stands. at'ditn v for signal the'relayl) o ne;;?:sneifing block is energized while relay'D deems: L gized. When signal B moves? stop so caution it establishes a connection iifc m'thje primary of transformer F to the of transformer-E also. Currentsofhot frequencies are, therefore, impressed on the primary of the track transformenyas-is shown for transformers 'F and Fflsothat the .current1in the track circuit is there-1 sultant of the two frequencies; consequently both relays D and D are energized and the signal 13 stands at clear. l 9o Comparing the arrangement of Flg. 2 with that of Fig. 1, it will be seen that the circuit connections of Fig. 2 are somewhat simpler, but that this arrangement-is somev what less economical in respect to current 9:; consumption, since, as long as the signals stand at clear or caution, the secondaries of each pair ot transformers E and E are connected in parallel through theresistances 9 so that a certain amount of current is "flowing through. these transformer secondaries, in series which produces no useful resu t.

Other connections of relay windings and of transformers for obtaining, in either relays or transformers the resultant of 'both those skilled in the art. Furthermore, while I have shownmy system in its simplest torm, it will be understood that it can be extended and modificdto cover various requirements in signaling which arise in practice. Accordingly, I do not desire to limit myself to the particular connections and arran ement of parts shown and described but sun in the appended claims to cover all modifications which re within the'scope of my invention. i I WhatI claim as new and desire to, secure by Letters Patent of the United States, is,-

1. In a block signal system, track circuits for the blocks, sources of current of different frequencies, supply connections for supplying currents from said sources to the track circuits, means controlled by train movements for varying-said supply connections to fvary the frequencies of the currents cup and a pair of track wind 8 supplied,

the track 139 plied. to the trackcircuits,

inns and cod rating windin circuits, one relay of each pair being responsive to current in the track circuit from the supply connections for that block reed to indicate gal dless of the variations in said. connections and the other relay being responsive to current wlth one arrangement only of said supply connections.

2. In ablock' signal system, track circuits for the blocks, si n'als for the blocks adaptanger, caution and clear, sources of current of different frequencies, supply connections for supplying current from said sources to the track circuits,

means controlled by the movement of a "in'the supply connections and the other relay being responsive to currentwvilli onearrangement;only of said supplya ncctions.

3. In a block signal syslenn'ajt'rark circuits for, the blocks, means controlled by train movements for supplying to the trac k cireuit of each block currents of eitlior f u frequencies, and a air of true H s per block'havingtracr windings and coiiperutbig/windings supplied with current iudepeiidently of are track circuits, said co i ip'era 'ng windings being supplied with botlL ma a-ice in ma j'cla'yut-each pair and with only one frequency in the other relay of the pair.

4. I n a block signal system, track circuits 'for the l)locks, signals for the blocks adapted to indicate danger, caution and clear, sources of current of two different frequencies, sup

ply connections for supplying current from said sources to the truck circuits of the blocks, mcanscontrolled hy the uneven; t of a signal from danger torautionkfor shifting.

the supply conncctions of the-j preceding block from one frequency to the other, and a pair of track relays per hlpck. contr'll'n the signal indications, having rac p ings and cotiiitirating windin s 'dsupplled with current independently of 't e'track circuits. said cooperating windingsfbeing snpplied with both frequenciesincpne relay of each pair and with only one frequency in the other rclay of the pair.

in a block signal system, track circuits for the blocks, means controlled b' train movements for supplying to the true circuit of each block currents of different f equencies, and a pairof'track relays'per ck having track windings and cooperat- 'i'rig windings supplied with current independcnlly of the track circuits, one relay of each pair being responsive to each current supplied to the track circuitof the block and the other relay being'rcsponsivc to onset said currents only i In witness whereof, I have hereunto set my hand this first day of October, 1909,

LAURENCE A. HAWKINS. Witnesses:

BENJAMIN B. l ll'lin, ill-1m: a (heroin). 

